The swash plate compressor is so constructed that inside a housing where a refrigerant is present, a rotational motion of a swash plate mounted perpendicularly and obliquely on a rotational shaft by directly fixing the swash plate to the rotational shaft or indirectly fixing the swash plate thereto through a coupling member is converted into a reciprocating motion of a piston through a semispherical shoe to be subjected to sliding contact with the swash plate to compress and expand the refrigerant. The swash plate compressor is classified into a double swash plate type of compressing and expanding the refrigerant at both sides of the swash plate by using a double head type piston and a single swash plate type of compressing and expanding the refrigerant at one side thereof by using a single head type piston. The semispherical shoe includes a type which slides on only one side surface of the swash plate and a type which slides on both side surfaces thereof. In these swash plate compressors, sliding having a high relative speed of not less 20 m is generated per second on a sliding contact surface of the swash plate and that of the semispherical shoe. Thus the semispherical shoe is used in a very harsh environment.
In lubrication, lubricating oil circulates inside the housing, with the lubricating oil being blended into the refrigerant and diluted and is supplied to sliding contact portions in the form of mist. When an operation is resumed in an operation-suspended state, the lubricating oil is washed away by the vaporized refrigerant. As a result, when the operation is resumed, the sliding contact surface of the swash plate and that of the semispherical shoe have a dry lubricated state in which the lubricating oil is not supplied thereto. As a result, the sliding contact surfaces thereof are liable to be subjected to seizure.
As means for preventing sliding contact surface of the swash plate and that of the semispherical shoe from being subjected to the seizure, there is proposed the resin film, consisting of polyether ether ketone (PEEK), which is directly formed on at least the sliding contact surface of the swash plate and that of the semispherical shoe by using an electrostatic powder coating method (see patent document 1). There is also proposed the thermoplastic polyimide film, containing the solid lubricant, which is formed on the sliding contact surface thereof by using the electrostatic powder coating method (see patent document 2).
To secure a high sliding contact property in a high speed and high temperature condition, there is proposed the semispherical shoe for the swash plate compressor in which the sliding contact layer composed of the binder consisting of the PEEK resin and the solid lubricant dispersed in the binder is formed on the sliding contact portion of at least one of the swash plate, the semispherical shoe, and the piston (see patent document 3).